Fix a compiler warning
Fix a compiler warning

djdeath/cogl-android,djdeath/cogl,djdeath/cogl-android,Distrotech/cogl,djdeath/cogl-android,spatulasnout/cogl,gcampax/cogl,Distrotech/cogl,spatulasnout/cogl,collects/cogl,djdeath/cogl,gcampax/cogl,gcampax/cogl,Distrotech/cogl,Distrotech/cogl,gcampax/cogl,collects/cogl,djdeath/cogl